1. Field of the Invention
The present invention relates to an apparatus and a method for tracing position and direction of a target object, and more particularly, to an apparatus and a method for tracing position and direction of a target object through a radio frequency (RF) signal.
This work was supported by the IT R&D program of MIC/IITA [2005-S-092-02, USN-based Ubiquitous Robotic Space Technology Development]
2. Description of the Related Art
In general, an apparatus for tracing position and direction of a target object has been studied in various fields to provide more services to human life, and its technical development is being already in great progress.
One of its examples is the global positioning system (GPS). Developed by the United States Department of Defense, the GPS utilizes a constellation of earth orbit satellites that transmit precise microwave signals, and thus enables a GPS receiver to determine its location, speed/direction and time.
However, the GPS basically includes various operative errors, and the operative errors increase due to a variety of factors such as arrangements of satellites, weather conditions, buildings, and forests, which may affect a GPS signal reception. Most importantly, The GPS may not be feasible indoors because there are limitations in receiving a GPS signal.
Another example is a position tracking system utilizing a camera image. This stores an image of an already-known object in advance, and compares and matches the stored object image with an image that is obtained through a camera in order to search for a corresponding object, such that its existence and direction can be achieved.
However, this position tracking system is extremely sensitive to a lighting change. As a result, this may have a limitation in searching for a target object, because it is difficult to recognize direction, position, and a size change of the target object in a dark environment.
Furthermore, as circumstances require, the position tracking system may utilize a moving speed of a sound source, and also may place sound source sensors in a circular disposition by using a center axis as a reference line. Then, the position tracking system determines that the target object is disposed close to the one sound source sensor that first detects the sound source of the target object among the sound source sensors. However, this position tracking system is especially sensitive to surrounding noise because of its operating property that utilizes a sound source, and thus may not be appropriately functioned in general environments.
Reliability and performance of the position tracking system may vary according to surrounding environments.